Semi-conservative transmission of DNA N6-adenine methylation in a unicellular eukaryote

Taking advantage of Single Molecule Real-Time Circular Consensus Sequencing (SMRT CCS), we provide definitive evidence for semi-conservative transmission of 6mA in the unicellular eukaryote Tetrahymena thermophila. Our study dissects AMT1-dependent maintenance methylation and AMT1-independent de novo methylation, reveals a molecular pathway for 6mA transmission with striking similarity to 5-methyl cytosine (5mC) transmission at the CpG dinucleotide, and establishes 6mA as a bona fide eukaryotic epigenetic mark.